/*
 * SPDX-License-Identifier: Apache-2.0
 *
 * The OpenSearch Contributors require contributions made to
 * this file be licensed under the Apache-2.0 license or a
 * compatible open source license.
 */

/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch licenses this file to you under
 * the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/*
 * Modifications Copyright OpenSearch Contributors. See
 * GitHub history for details.
 */

package org.opensearch.search.aggregations.bucket;

import org.opensearch.OpenSearchException;
import org.opensearch.action.index.IndexRequestBuilder;
import org.opensearch.action.search.SearchResponse;
import org.opensearch.common.settings.Settings;
import org.opensearch.index.fielddata.ScriptDocValues;
import org.opensearch.index.query.QueryBuilders;
import org.opensearch.plugins.Plugin;
import org.opensearch.script.Script;
import org.opensearch.script.ScriptType;
import org.opensearch.search.aggregations.AggregationTestScriptsPlugin;
import org.opensearch.search.aggregations.Aggregator.SubAggCollectionMode;
import org.opensearch.search.aggregations.BucketOrder;
import org.opensearch.search.aggregations.bucket.filter.Filter;
import org.opensearch.search.aggregations.bucket.terms.IncludeExclude;
import org.opensearch.search.aggregations.bucket.terms.Terms;
import org.opensearch.search.aggregations.bucket.terms.Terms.Bucket;
import org.opensearch.search.aggregations.metrics.Avg;
import org.opensearch.search.aggregations.metrics.Max;
import org.opensearch.search.aggregations.metrics.Stats;
import org.opensearch.search.aggregations.metrics.ExtendedStats;
import org.opensearch.search.aggregations.metrics.Sum;
import org.opensearch.test.OpenSearchIntegTestCase;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;

import static org.opensearch.common.xcontent.XContentFactory.jsonBuilder;
import static org.opensearch.search.aggregations.AggregationBuilders.avg;
import static org.opensearch.search.aggregations.AggregationBuilders.extendedStats;
import static org.opensearch.search.aggregations.AggregationBuilders.filter;
import static org.opensearch.search.aggregations.AggregationBuilders.max;
import static org.opensearch.search.aggregations.AggregationBuilders.stats;
import static org.opensearch.search.aggregations.AggregationBuilders.sum;
import static org.opensearch.search.aggregations.AggregationBuilders.terms;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertSearchResponse;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.core.IsNull.notNullValue;

@OpenSearchIntegTestCase.SuiteScopeTestCase
public class LongTermsIT extends AbstractTermsTestCase {

    @Override
    protected Collection<Class<? extends Plugin>> nodePlugins() {
        return Collections.singleton(CustomScriptPlugin.class);
    }

    public static class CustomScriptPlugin extends AggregationTestScriptsPlugin {

        @Override
        protected Map<String, Function<Map<String, Object>, Object>> pluginScripts() {
            Map<String, Function<Map<String, Object>, Object>> scripts = super.pluginScripts();

            scripts.put("floor(_value / 1000 + 1)", vars -> Math.floor((double) vars.get("_value") / 1000 + 1));

            scripts.put("doc['" + MULTI_VALUED_FIELD_NAME + "']", vars -> {
                Map<?, ?> doc = (Map) vars.get("doc");
                return doc.get(MULTI_VALUED_FIELD_NAME);
            });

            scripts.put("doc['" + SINGLE_VALUED_FIELD_NAME + "'].value", vars -> {
                Map<?, ?> doc = (Map) vars.get("doc");
                ScriptDocValues.Longs value = (ScriptDocValues.Longs) doc.get(SINGLE_VALUED_FIELD_NAME);
                return value.getValue();
            });

            return scripts;
        }

        @Override
        protected Map<String, Function<Map<String, Object>, Object>> nonDeterministicPluginScripts() {
            Map<String, Function<Map<String, Object>, Object>> scripts = new HashMap<>();

            scripts.put("Math.random()", vars -> LongTermsIT.randomDouble());

            return scripts;
        }
    }

    private static final int NUM_DOCS = 5; // TODO randomize the size?
    private static final String SINGLE_VALUED_FIELD_NAME = "l_value";
    private static final String MULTI_VALUED_FIELD_NAME = "l_values";
    private static HashMap<Long, Map<String, Object>> expectedMultiSortBuckets;

    @Override
    public void setupSuiteScopeCluster() throws Exception {
        createIndex("idx", "high_card_idx");
        IndexRequestBuilder[] lowCardBuilders = new IndexRequestBuilder[NUM_DOCS];
        for (int i = 0; i < lowCardBuilders.length; i++) {
            lowCardBuilders[i] = client().prepareIndex("idx")
                .setSource(
                    jsonBuilder().startObject()
                        .field(SINGLE_VALUED_FIELD_NAME, i)
                        .startArray(MULTI_VALUED_FIELD_NAME)
                        .value(i)
                        .value(i + 1)
                        .endArray()
                        .field("num_tag", i < lowCardBuilders.length / 2 + 1 ? 1 : 0) // used to test order by single-bucket sub agg
                        .field("constant", 1)
                        .endObject()
                );
        }
        indexRandom(true, lowCardBuilders);
        IndexRequestBuilder[] highCardBuilders = new IndexRequestBuilder[100]; // TODO randomize the size?
        for (int i = 0; i < highCardBuilders.length; i++) {
            highCardBuilders[i] = client().prepareIndex("high_card_idx")
                .setSource(
                    jsonBuilder().startObject()
                        .field(SINGLE_VALUED_FIELD_NAME, i)
                        .startArray(MULTI_VALUED_FIELD_NAME)
                        .value(i)
                        .value(i + 1)
                        .endArray()
                        .endObject()
                );

        }
        indexRandom(true, highCardBuilders);
        createIndex("idx_unmapped");

        assertAcked(prepareCreate("empty_bucket_idx").setMapping(SINGLE_VALUED_FIELD_NAME, "type=integer"));
        List<IndexRequestBuilder> builders = new ArrayList<>();
        for (int i = 0; i < 2; i++) {
            builders.add(
                client().prepareIndex("empty_bucket_idx")
                    .setId("" + i)
                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, i * 2).endObject())
            );
        }

        getMultiSortDocs(builders);

        indexRandom(true, builders.toArray(new IndexRequestBuilder[builders.size()]));
        ensureSearchable();
    }

    private void getMultiSortDocs(List<IndexRequestBuilder> builders) throws IOException {
        expectedMultiSortBuckets = new HashMap<>();
        Map<String, Object> bucketProps = new HashMap<>();
        bucketProps.put("_term", 1L);
        bucketProps.put("_count", 3L);
        bucketProps.put("avg_l", 1d);
        bucketProps.put("sum_d", 6d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 2L);
        bucketProps.put("_count", 3L);
        bucketProps.put("avg_l", 2d);
        bucketProps.put("sum_d", 6d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 3L);
        bucketProps.put("_count", 2L);
        bucketProps.put("avg_l", 3d);
        bucketProps.put("sum_d", 3d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 4L);
        bucketProps.put("_count", 2L);
        bucketProps.put("avg_l", 3d);
        bucketProps.put("sum_d", 4d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 5L);
        bucketProps.put("_count", 2L);
        bucketProps.put("avg_l", 5d);
        bucketProps.put("sum_d", 3d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 6L);
        bucketProps.put("_count", 1L);
        bucketProps.put("avg_l", 5d);
        bucketProps.put("sum_d", 1d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);
        bucketProps = new HashMap<>();
        bucketProps.put("_term", 7L);
        bucketProps.put("_count", 1L);
        bucketProps.put("avg_l", 5d);
        bucketProps.put("sum_d", 1d);
        expectedMultiSortBuckets.put((Long) bucketProps.get("_term"), bucketProps);

        createIndex("sort_idx");
        for (int i = 1; i <= 3; i++) {
            builders.add(
                client().prepareIndex("sort_idx")
                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 1).field("l", 1).field("d", i).endObject())
            );
            builders.add(
                client().prepareIndex("sort_idx")
                    .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 2).field("l", 2).field("d", i).endObject())
            );
        }
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 3).field("l", 3).field("d", 1).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 3).field("l", 3).field("d", 2).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 4).field("l", 3).field("d", 1).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 4).field("l", 3).field("d", 3).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 5).field("l", 5).field("d", 1).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 5).field("l", 5).field("d", 2).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 6).field("l", 5).field("d", 1).endObject())
        );
        builders.add(
            client().prepareIndex("sort_idx")
                .setSource(jsonBuilder().startObject().field(SINGLE_VALUED_FIELD_NAME, 7).field("l", 5).field("d", 1).endObject())
        );
    }

    private String key(Terms.Bucket bucket) {
        return bucket.getKeyAsString();
    }

    // the main purpose of this test is to make sure we're not allocating 2GB of memory per shard
    public void testSizeIsZero() {
        IllegalArgumentException exception = expectThrows(
            IllegalArgumentException.class,
            () -> client().prepareSearch("high_card_idx")
                .addAggregation(
                    terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                        .collectMode(randomFrom(SubAggCollectionMode.values()))
                        .minDocCount(randomInt(1))
                        .size(0)
                )
                .get()
        );
        assertThat(exception.getMessage(), containsString("[size] must be greater than 0. Found [0] in [terms]"));
    }

    public void testSingleValueFieldWithPartitionedFiltering() throws Exception {
        runTestFieldWithPartitionedFiltering(SINGLE_VALUED_FIELD_NAME);
    }

    public void testMultiValueFieldWithPartitionedFiltering() throws Exception {
        runTestFieldWithPartitionedFiltering(MULTI_VALUED_FIELD_NAME);
    }

    private void runTestFieldWithPartitionedFiltering(String field) throws Exception {
        // Find total number of unique terms
        SearchResponse allResponse = client().prepareSearch("idx")
            .addAggregation(terms("terms").field(field).collectMode(randomFrom(SubAggCollectionMode.values())))
            .get();
        assertSearchResponse(allResponse);
        Terms terms = allResponse.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        int expectedCardinality = terms.getBuckets().size();

        // Gather terms using partitioned aggregations
        final int numPartitions = randomIntBetween(2, 4);
        Set<Number> foundTerms = new HashSet<>();
        for (int partition = 0; partition < numPartitions; partition++) {
            SearchResponse response = client().prepareSearch("idx")
                .addAggregation(
                    terms("terms").field(field)
                        .includeExclude(new IncludeExclude(partition, numPartitions))
                        .collectMode(randomFrom(SubAggCollectionMode.values()))
                )
                .get();
            assertSearchResponse(response);
            terms = response.getAggregations().get("terms");
            assertThat(terms, notNullValue());
            assertThat(terms.getName(), equalTo("terms"));
            for (Bucket bucket : terms.getBuckets()) {
                assertFalse(foundTerms.contains(bucket.getKeyAsNumber()));
                foundTerms.add(bucket.getKeyAsNumber());
            }
        }
        assertEquals(expectedCardinality, foundTerms.size());
    }

    public void testSingleValuedFieldWithValueScript() throws Exception {
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .script(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_value + 1", Collections.emptyMap()))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + (i + 1d));
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + (i + 1d)));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i + 1));
            assertThat(bucket.getDocCount(), equalTo(1L));
        }
    }

    public void testMultiValuedFieldWithValueScript() throws Exception {
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(MULTI_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .script(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_value - 1", Collections.emptyMap()))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(6));

        for (int i = 0; i < 6; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + (i - 1d));
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + (i - 1d)));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i - 1));
            if (i == 0 || i == 5) {
                assertThat(bucket.getDocCount(), equalTo(1L));
            } else {
                assertThat(bucket.getDocCount(), equalTo(2L));
            }
        }
    }

    public void testMultiValuedFieldWithValueScriptNotUnique() throws Exception {
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(MULTI_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .script(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "floor(_value / 1000 + 1)", Collections.emptyMap()))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(1));

        Terms.Bucket bucket = terms.getBucketByKey("1.0");
        assertThat(bucket, notNullValue());
        assertThat(key(bucket), equalTo("1.0"));
        assertThat(bucket.getKeyAsNumber().intValue(), equalTo(1));
        assertThat(bucket.getDocCount(), equalTo(5L));
    }

    /*

    [1, 2]
    [2, 3]
    [3, 4]
    [4, 5]
    [5, 6]

    1 - count: 1 - sum: 1
    2 - count: 2 - sum: 4
    3 - count: 2 - sum: 6
    4 - count: 2 - sum: 8
    5 - count: 2 - sum: 10
    6 - count: 1 - sum: 6

    */

    public void testScriptSingleValue() throws Exception {
        Script script = new Script(
            ScriptType.INLINE,
            CustomScriptPlugin.NAME,
            "doc['" + SINGLE_VALUED_FIELD_NAME + "'].value",
            Collections.emptyMap()
        );

        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(terms("terms").collectMode(randomFrom(SubAggCollectionMode.values())).script(script))
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i));
            assertThat(bucket.getKeyAsNumber(), instanceOf(Long.class));
            assertThat(bucket.getDocCount(), equalTo(1L));
        }
    }

    public void testScriptMultiValued() throws Exception {
        Script script = new Script(
            ScriptType.INLINE,
            CustomScriptPlugin.NAME,
            "doc['" + MULTI_VALUED_FIELD_NAME + "']",
            Collections.emptyMap()
        );

        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(terms("terms").collectMode(randomFrom(SubAggCollectionMode.values())).script(script))
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(6));

        for (int i = 0; i < 6; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i));
            if (i == 0 || i == 5) {
                assertThat(bucket.getDocCount(), equalTo(1L));
            } else {
                assertThat(bucket.getDocCount(), equalTo(2L));
            }
        }
    }

    public void testPartiallyUnmapped() throws Exception {
        SearchResponse response = client().prepareSearch("idx_unmapped", "idx")
            .addAggregation(terms("terms").field(SINGLE_VALUED_FIELD_NAME).collectMode(randomFrom(SubAggCollectionMode.values())))
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i));
            assertThat(bucket.getDocCount(), equalTo(1L));
        }
    }

    public void testPartiallyUnmappedWithFormat() throws Exception {
        SearchResponse response = client().prepareSearch("idx_unmapped", "idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME).collectMode(randomFrom(SubAggCollectionMode.values())).format("0000")
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            String key = String.format(Locale.ROOT, "%04d", i);
            Terms.Bucket bucket = terms.getBucketByKey(key);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo(key));
            assertThat(bucket.getKeyAsNumber().intValue(), equalTo(i));
            assertThat(bucket.getDocCount(), equalTo(1L));
        }
    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscWithTermsSubAgg() throws Exception {
        boolean asc = true;
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("avg_i", asc))
                    .subAggregation(avg("avg_i").field(SINGLE_VALUED_FIELD_NAME))
                    .subAggregation(terms("subTerms").field(MULTI_VALUED_FIELD_NAME).collectMode(randomFrom(SubAggCollectionMode.values())))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getDocCount(), equalTo(1L));

            Avg avg = bucket.getAggregations().get("avg_i");
            assertThat(avg, notNullValue());
            assertThat(avg.getValue(), equalTo((double) i));

            Terms subTermsAgg = bucket.getAggregations().get("subTerms");
            assertThat(subTermsAgg, notNullValue());
            assertThat(subTermsAgg.getBuckets().size(), equalTo(2));
            int j = i;
            for (Terms.Bucket subBucket : subTermsAgg.getBuckets()) {
                assertThat(subBucket, notNullValue());
                assertThat(key(subBucket), equalTo(String.valueOf(j)));
                assertThat(subBucket.getDocCount(), equalTo(1L));
                j++;
            }
        }
    }

    public void testSingleValuedFieldOrderedBySingleBucketSubAggregationAsc() throws Exception {
        boolean asc = randomBoolean();
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("num_tags").field("num_tag")
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("filter", asc))
                    .subAggregation(filter("filter", QueryBuilders.matchAllQuery()))
            )
            .get();

        assertSearchResponse(response);

        Terms tags = response.getAggregations().get("num_tags");
        assertThat(tags, notNullValue());
        assertThat(tags.getName(), equalTo("num_tags"));
        assertThat(tags.getBuckets().size(), equalTo(2));

        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();

        Terms.Bucket tag = iters.next();
        assertThat(tag, notNullValue());
        assertThat(key(tag), equalTo(asc ? "0" : "1"));
        assertThat(tag.getDocCount(), equalTo(asc ? 2L : 3L));
        Filter filter = tag.getAggregations().get("filter");
        assertThat(filter, notNullValue());
        assertThat(filter.getDocCount(), equalTo(asc ? 2L : 3L));

        tag = iters.next();
        assertThat(tag, notNullValue());
        assertThat(key(tag), equalTo(asc ? "1" : "0"));
        assertThat(tag.getDocCount(), equalTo(asc ? 3L : 2L));
        filter = tag.getAggregations().get("filter");
        assertThat(filter, notNullValue());
        assertThat(filter.getDocCount(), equalTo(asc ? 3L : 2L));
    }

    public void testSingleValuedFieldOrderedBySubAggregationAscMultiHierarchyLevels() throws Exception {
        boolean asc = randomBoolean();
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("tags").field("num_tag")
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("filter1>filter2>max", asc))
                    .subAggregation(
                        filter("filter1", QueryBuilders.matchAllQuery()).subAggregation(
                            filter("filter2", QueryBuilders.matchAllQuery()).subAggregation(max("max").field(SINGLE_VALUED_FIELD_NAME))
                        )
                    )
            )
            .get();

        assertSearchResponse(response);

        Terms tags = response.getAggregations().get("tags");
        assertThat(tags, notNullValue());
        assertThat(tags.getName(), equalTo("tags"));
        assertThat(tags.getBuckets().size(), equalTo(2));

        Iterator<? extends Terms.Bucket> iters = tags.getBuckets().iterator();

        // the max for "1" is 2
        // the max for "0" is 4

        Terms.Bucket tag = iters.next();
        assertThat(tag, notNullValue());
        assertThat(key(tag), equalTo(asc ? "1" : "0"));
        assertThat(tag.getDocCount(), equalTo(asc ? 3L : 2L));
        Filter filter1 = tag.getAggregations().get("filter1");
        assertThat(filter1, notNullValue());
        assertThat(filter1.getDocCount(), equalTo(asc ? 3L : 2L));
        Filter filter2 = filter1.getAggregations().get("filter2");
        assertThat(filter2, notNullValue());
        assertThat(filter2.getDocCount(), equalTo(asc ? 3L : 2L));
        Max max = filter2.getAggregations().get("max");
        assertThat(max, notNullValue());
        assertThat(max.getValue(), equalTo(asc ? 2.0 : 4.0));

        tag = iters.next();
        assertThat(tag, notNullValue());
        assertThat(key(tag), equalTo(asc ? "0" : "1"));
        assertThat(tag.getDocCount(), equalTo(asc ? 2L : 3L));
        filter1 = tag.getAggregations().get("filter1");
        assertThat(filter1, notNullValue());
        assertThat(filter1.getDocCount(), equalTo(asc ? 2L : 3L));
        filter2 = filter1.getAggregations().get("filter2");
        assertThat(filter2, notNullValue());
        assertThat(filter2.getDocCount(), equalTo(asc ? 2L : 3L));
        max = filter2.getAggregations().get("max");
        assertThat(max, notNullValue());
        assertThat(max.getValue(), equalTo(asc ? 4.0 : 2.0));
    }

    public void testSingleValuedFieldOrderedByMissingSubAggregation() throws Exception {
        for (String index : Arrays.asList("idx", "idx_unmapped")) {
            try {
                client().prepareSearch(index)
                    .addAggregation(
                        terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                            .collectMode(randomFrom(SubAggCollectionMode.values()))
                            .order(BucketOrder.aggregation("avg_i", true))
                    )
                    .get();

                fail("Expected search to fail when trying to sort terms aggregation by sug-aggregation that doesn't exist");

            } catch (OpenSearchException e) {
                // expected
            }
        }
    }

    public void testSingleValuedFieldOrderedByNonMetricsOrMultiBucketSubAggregation() throws Exception {
        for (String index : Arrays.asList("idx", "idx_unmapped")) {
            try {
                client().prepareSearch(index)
                    .addAggregation(
                        terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                            .collectMode(randomFrom(SubAggCollectionMode.values()))
                            .order(BucketOrder.aggregation("num_tags", true))
                            .subAggregation(terms("num_tags").field("num_tags").collectMode(randomFrom(SubAggCollectionMode.values())))
                    )
                    .get();

                fail("Expected search to fail when trying to sort terms aggregation by sug-aggregation which is not of a metrics type");

            } catch (OpenSearchException e) {
                // expected
            }
        }
    }

    public void testSingleValuedFieldOrderedByMultiValuedSubAggregationWithUnknownMetric() throws Exception {
        for (String index : Arrays.asList("idx", "idx_unmapped")) {
            try {
                client().prepareSearch(index)
                    .addAggregation(
                        terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                            .collectMode(randomFrom(SubAggCollectionMode.values()))
                            .order(BucketOrder.aggregation("stats.foo", true))
                            .subAggregation(stats("stats").field(SINGLE_VALUED_FIELD_NAME))
                    )
                    .get();

                fail(
                    "Expected search to fail when trying to sort terms aggregation by multi-valued sug-aggregation "
                        + "with an unknown specified metric to order by"
                );

            } catch (OpenSearchException e) {
                // expected
            }
        }
    }

    public void testSingleValuedFieldOrderedByMultiValuedSubAggregationWithoutMetric() throws Exception {
        for (String index : Arrays.asList("idx", "idx_unmapped")) {
            try {
                client().prepareSearch(index)
                    .addAggregation(
                        terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                            .collectMode(randomFrom(SubAggCollectionMode.values()))
                            .order(BucketOrder.aggregation("stats", true))
                            .subAggregation(stats("stats").field(SINGLE_VALUED_FIELD_NAME))
                    )
                    .get();

                fail(
                    "Expected search to fail when trying to sort terms aggregation by multi-valued sug-aggregation "
                        + "where the metric name is not specified"
                );

            } catch (OpenSearchException e) {
                // expected
            }
        }
    }

    public void testSingleValuedFieldOrderedByMultiValueSubAggregationAsc() throws Exception {
        boolean asc = true;
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("stats.avg", asc))
                    .subAggregation(stats("stats").field(SINGLE_VALUED_FIELD_NAME))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getDocCount(), equalTo(1L));

            Stats stats = bucket.getAggregations().get("stats");
            assertThat(stats, notNullValue());
            assertThat(stats.getMax(), equalTo((double) i));
        }

    }

    public void testSingleValuedFieldOrderedByMultiValueSubAggregationDesc() throws Exception {
        boolean asc = false;
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("stats.avg", asc))
                    .subAggregation(stats("stats").field(SINGLE_VALUED_FIELD_NAME))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 4; i >= 0; i--) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getDocCount(), equalTo(1L));

            Stats stats = bucket.getAggregations().get("stats");
            assertThat(stats, notNullValue());
            assertThat(stats.getMax(), equalTo((double) i));
        }

    }

    public void testSingleValuedFieldOrderedByMultiValueExtendedStatsAsc() throws Exception {
        boolean asc = true;
        SearchResponse response = client().prepareSearch("idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.aggregation("stats.variance", asc))
                    .subAggregation(extendedStats("stats").field(SINGLE_VALUED_FIELD_NAME))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(5));

        for (int i = 0; i < 5; i++) {
            Terms.Bucket bucket = terms.getBucketByKey("" + i);
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo("" + i));
            assertThat(bucket.getDocCount(), equalTo(1L));

            ExtendedStats stats = bucket.getAggregations().get("stats");
            assertThat(stats, notNullValue());
            assertThat(stats.getMax(), equalTo((double) i));
        }

    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscAndTermsDesc() throws Exception {
        long[] expectedKeys = new long[] { 1, 2, 4, 3, 7, 6, 5 };
        assertMultiSortResponse(expectedKeys, BucketOrder.aggregation("avg_l", true), BucketOrder.key(false));
    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscAndTermsAsc() throws Exception {
        long[] expectedKeys = new long[] { 1, 2, 3, 4, 5, 6, 7 };
        assertMultiSortResponse(expectedKeys, BucketOrder.aggregation("avg_l", true), BucketOrder.key(true));
    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationDescAndTermsAsc() throws Exception {
        long[] expectedKeys = new long[] { 5, 6, 7, 3, 4, 2, 1 };
        assertMultiSortResponse(expectedKeys, BucketOrder.aggregation("avg_l", false), BucketOrder.key(true));
    }

    public void testSingleValuedFieldOrderedByCountAscAndSingleValueSubAggregationAsc() throws Exception {
        long[] expectedKeys = new long[] { 6, 7, 3, 4, 5, 1, 2 };
        assertMultiSortResponse(expectedKeys, BucketOrder.count(true), BucketOrder.aggregation("avg_l", true));
    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscSingleValueSubAggregationAsc() throws Exception {
        long[] expectedKeys = new long[] { 6, 7, 3, 5, 4, 1, 2 };
        assertMultiSortResponse(expectedKeys, BucketOrder.aggregation("sum_d", true), BucketOrder.aggregation("avg_l", true));
    }

    public void testSingleValuedFieldOrderedByThreeCriteria() throws Exception {
        long[] expectedKeys = new long[] { 2, 1, 4, 5, 3, 6, 7 };
        assertMultiSortResponse(
            expectedKeys,
            BucketOrder.count(false),
            BucketOrder.aggregation("sum_d", false),
            BucketOrder.aggregation("avg_l", false)
        );
    }

    public void testSingleValuedFieldOrderedBySingleValueSubAggregationAscAsCompound() throws Exception {
        long[] expectedKeys = new long[] { 1, 2, 3, 4, 5, 6, 7 };
        assertMultiSortResponse(expectedKeys, BucketOrder.aggregation("avg_l", true));
    }

    private void assertMultiSortResponse(long[] expectedKeys, BucketOrder... order) {
        SearchResponse response = client().prepareSearch("sort_idx")
            .addAggregation(
                terms("terms").field(SINGLE_VALUED_FIELD_NAME)
                    .collectMode(randomFrom(SubAggCollectionMode.values()))
                    .order(BucketOrder.compound(order))
                    .subAggregation(avg("avg_l").field("l"))
                    .subAggregation(sum("sum_d").field("d"))
            )
            .get();

        assertSearchResponse(response);

        Terms terms = response.getAggregations().get("terms");
        assertThat(terms, notNullValue());
        assertThat(terms.getName(), equalTo("terms"));
        assertThat(terms.getBuckets().size(), equalTo(expectedKeys.length));

        int i = 0;
        for (Terms.Bucket bucket : terms.getBuckets()) {
            assertThat(bucket, notNullValue());
            assertThat(key(bucket), equalTo(String.valueOf(expectedKeys[i])));
            assertThat(bucket.getDocCount(), equalTo(expectedMultiSortBuckets.get(expectedKeys[i]).get("_count")));
            Avg avg = bucket.getAggregations().get("avg_l");
            assertThat(avg, notNullValue());
            assertThat(avg.getValue(), equalTo(expectedMultiSortBuckets.get(expectedKeys[i]).get("avg_l")));
            Sum sum = bucket.getAggregations().get("sum_d");
            assertThat(sum, notNullValue());
            assertThat(sum.getValue(), equalTo(expectedMultiSortBuckets.get(expectedKeys[i]).get("sum_d")));
            i++;
        }
    }

    public void testOtherDocCount() {
        testOtherDocCount(SINGLE_VALUED_FIELD_NAME, MULTI_VALUED_FIELD_NAME);
    }

    /**
     * Make sure that a request using a deterministic script or not using a script get cached.
     * Ensure requests using nondeterministic scripts do not get cached.
     */
    public void testScriptCaching() throws Exception {
        assertAcked(
            prepareCreate("cache_test_idx").setMapping("d", "type=long")
                .setSettings(Settings.builder().put("requests.cache.enable", true).put("number_of_shards", 1).put("number_of_replicas", 1))
                .get()
        );
        indexRandom(
            true,
            client().prepareIndex("cache_test_idx").setId("1").setSource("s", 1),
            client().prepareIndex("cache_test_idx").setId("2").setSource("s", 2)
        );

        // Make sure we are starting with a clear cache
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(0L)
        );

        // Test that a request using a nondeterministic script does not get cached
        SearchResponse r = client().prepareSearch("cache_test_idx")
            .setSize(0)
            .addAggregation(
                terms("terms").field("d")
                    .script(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "Math.random()", Collections.emptyMap()))
            )
            .get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(0L)
        );

        // Test that a request using a deterministic script gets cached
        r = client().prepareSearch("cache_test_idx")
            .setSize(0)
            .addAggregation(
                terms("terms").field("d")
                    .script(new Script(ScriptType.INLINE, CustomScriptPlugin.NAME, "_value + 1", Collections.emptyMap()))
            )
            .get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(1L)
        );

        // Ensure that non-scripted requests are cached as normal
        r = client().prepareSearch("cache_test_idx").setSize(0).addAggregation(terms("terms").field("d")).get();
        assertSearchResponse(r);

        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getHitCount(),
            equalTo(0L)
        );
        assertThat(
            client().admin()
                .indices()
                .prepareStats("cache_test_idx")
                .setRequestCache(true)
                .get()
                .getTotal()
                .getRequestCache()
                .getMissCount(),
            equalTo(2L)
        );
    }
}
